Closure cap



l Jan. 3l, 1967 s. KAvALus 3,301,426

CLOSURLl CAP Filed June 5, 1964 2 Sheets-Sheet l 'T1 V T'LCVL- y n /a ATTORNEY BY al@ M9-A,

, 'Filed June 5, 1964 Jn; 31, 1967 L. s. KAvALus l 3,301,425

CLOSURE CAP 2 Sheets-Sheet 2 'T1 ATTORNEY United States Patent O 3,301,426 cLosURE CAP ALeonard S.,Kavalus, Livingston, NJ., assignor to Ameri- This invention relates to finger grip tear-off closure caps for container openings and to methods for forming the same and is particularly concerned with such caps formed of thin lightweight metal which caps, when secured over the openings of bottles, jars, cans and the like, effectively close and seal those openings, even against substantial pressure, but are nevertheless easily hand destructible for removal.

In closure caps as heretofore devised, formed out of lightweight sheet material and provided with gripping ears to be gripped between the fingers for ready destruction and removal of the caps, and in the me-thod of manufacturing such caps, various problems have arisen. Probably the most serious and most difficult to overcome is the provision of scoring defining a tear strip which will leave sufficient metal of the cap to assure against failure under ythe pressures encountered in capping bottles of fluids, such as beer and soda water, but will stillienable the consumer, by grasping a tearing ear between the thumb and forenger, to pull and thus tear along the score lines with comparative ease so as to destroy the cap and get at the container contents. Uniformity of pull for cap rediameter of the initial blank at the bottom of the skirt to subs-tantially that of the cap top portion Where the skirt departs from the top.

It will be evident from what has just been said that the crowding of the metal gets progressively greater towards the free edge of the formed cylindrical skirt and thus the'` crowding and blocking, or other deformation of the scores, takes place in similar progression. It is not quite as simple as this, however, for the presence of the ear extending Iaway from the edge at one position has been found to introduce other factors interfering with ease of tearing. Additionally, even minute variations in manufacturing facilities, sometimes hardly detectable, render the blocking or disruptions in the scoring different from one cap to the next.

Other disturbing factors difficult of determination are introduced when such caps, after having been applied over the container openings are then acted on to secure them in place. This is done by forming the cylindrical necks radially inwardly to a cylindrical or other formation of still smaller diameter. This forming is commonly done by capping tools, operating on a spinning principal. Here, again, minor variations in settings of such things as spinning rolls introduce unexpected variations. At this stage, however, another source of variation comes into the picture, particularly if the container be of glass. This is because the necks, or finishes, on bottles, or other glass containers, though rformed to certain standards, are

not normally formed with the precision of machine made metal parts.

In seeking to overcome this difficult problem, it has been necessary to keep in mind t-hat retention of uniform easy tearing cannot be achieved at a sacrifice of tight se curing for pressure retention. Thus the efforts at a solution have largely been devoted to such aspects as modification of the scoring and to the extent and direction of it, and to the notching of the cap skirt in various manners in an effort to absorb the disruptive factors by one or more of these corrective factors without reducing the securing beyond what is needed. However, none of them, nor any combination of t-hem, have so far provided a solution of the problem. Some of these prior art developments have made the caps too weak in pressure retention. Others have made them too hard to remove and none of them, no matter how carefully they have been worked out, have succeeded in providing uniformity of removability, particularly in the range of the few pounds pull that must be the criterion if the product is to be universally acceptable to the general public. None of them, until the advent of the instant invention, have given full appreciation to the part the tearing e'ar plays in interfering with the desired removability. Certainly none of them have had any appreciation of how the tearing ear can be employed to provide a solution.

The cap and method of forming and lapplying same, in accordance with the invention, provides a real and complete solution to this overall problem. ing the stresses and strains right away from the scored area through providing Ian absorption area where -they can spend lthemselves without detracting from any of the advantageous aspects of the cap. It has, in accordance with the invention, surprisingly been found that when the tearear itself.

ing ear and the commencement of the tear strip aligned therewith have an absorption area imparted thereto neither in the initial stage of forming the cap out of the flat blank to a member with a flat top 'and a cylindrical skirt, nor in the securing stage involving contracting -that cylindrical skirt to secure the cap onto the bottle, are the provisions for tight securing and easy tearing interfered with to any material extent.

By slotting or removing a relatively narrow elongated portion of the tearing ear and of the tear strip continuing therefrom, the invention has provided a place in which the crowding of the metal of the skirt can be taken up. The invention has also removed the heretofore unappreciated disturbing effects caused by the presence of the It has done so in a manner and by means whose yieldability is such, with regard to the scored part of the skirt, that the deleterious deformation of the scores, as found in the prior art, is substantially eliminated. Instead, when equipped with the scoring designed to leave `sufficient metal to withstand the pressures imposed on the cap and yet to enable removal to beV effected by a pull within the poundage range acceptable to the public, the cap of the invention, after forming and securing, will perform as designed. Vln addition, it has incorporated in it a sufficient margin of flexibility that, regardless of normal variations in the surface of the con tainer to which the cap is to be applied, the cap of the invention will provide a tight seal and will be easily Y removable in the manner desired.

It is accordingly the principal object of this invention to It does so by tak-A provide new and improved tear-off closure caps for containers.

Another object is to provide a novel method for manufacturing such caps.

Another object is to provide a novel method for securing such caps over container openings.

Still another object of the invention is to provide such caps which though scored for removal by destruction through tearing, Will withstand with a minimum of weakening or variation the action of securing them to container openings.

Still another object of the invention is to provide such caps which are uniformly readily removably by destruc tion through tearing by the exertion of pulling power in a range which the public generally is capable of exerting.

A further object is to incorporate in such caps safeguards against undesirable variations in their removability resulting from variations in such things as manufacturing, applying and surfaces to which they are applied.

A further object is to provide hat scored cap blanks with adequate safeuard to minimize detrimental effects on the scores caused by the drawing of the cap skirt portion away from the top and/ or the subsequent contracting of the cap skirt in the applying of the cap.

A further object is to provide such safeguards, whether scored on its internal or external surface.

A still further object is to provide such caps with enhanced gripping facility in the tearing ear.

Further and more detailed objects of the invention will in part be obvious and in part appear as the description of the invention, taken in conjunction with the accompanying drawing proceeds.

In that drawing:

FIG. 1 is a bottom plan view of the cap blank for use in forming the closure cap of the presently preferred form of the invention.

FIG. 2 is an enlarged fragmentary vertical sectional view taken on line 2-2 of FIG. 1 termed upside down and looking in the direction of the arrows:

FIG. 3 is an enlarged fragmentary vertical sectional view taken on line 3 3 of FIG. 1 and looking in the direction of the arrows:

FIG. 4 is a front elevational view of the completed cap in accordance with the invention:

FIG. 5 is a fragmentary vertical vsectional view taken on line 5 5 of FIG. 4 and looking in the direction of the arrows:

FIG. 6 is a front elevational view of the cap of the invention shown as secured in place on a container neck:

FIG. 7 is a vertical sectional view taken on lines 7--7 of FIG. 6 and looking in the direction of the arrows:

FIG. 8 is a fragmentary perspective view of a cornpleted cap as shown in FIG. 4 taken from the tearing ear side thereof: f

FIG. 9 is a similar view but showing the cap as it appears when sealed in place on a container neck or bottle finish as shown in FIG. 6.

FIG. 10 is a bottom plan view of a modified form of cap blank:

FIG. 1l is a view similar to FIG. 6 of a cap formed from the blank of FIG. 10.

FIG. 12 is a View similar to FIG. 1 of a cap blank scored on the opposite surface from that of FIG. l.

FIG. 13 is an enlarged fragmentary section taken on line 13 13 of FIG. 12 and looking in the direction of the arrows, and

FIG. 14 is a view similar to FIG. 4 but showing an exteriorly scored cap as formed from the blank of FIG. 12.

Considering first the general aspects of the closure cap of the invention as shown in FIGS. 4 and 5, the cap generally indicated at 1 comprises a flat disc-like top 2, surrounded by a depending skirt 3 with the juncture of the top and skirt being indicated at 4. The skirt 3 terminates in a downwardly facing free end edge S, which edge, except for the portion from which the gripping ear 6 extends, forms a complete circle. The ear 6 extends directly downwardly from the skirt for a `short distance in a neck portion 7 and then turns radially outwardly on a somewhat ydownward incline away from the cap. The ear side edges 8 and 9 taper slightly inwardly toward each other throughout their extent from the free edge of the skirt to their rounded ear end portion 10.

The cap 1 has either i-ts interior surface a or exterior surface b as desired, scored along a pair of lines. The score lines may also follow any particular pattern in their extent across the cap, such as diverging outwardly away from each other in either curved or straight lines. For the purpose of illustration, however, the scoring of the cap of FIGS. 4 and 5 is shown as being formed into the interior surface a` of the cap and as having portions 11 and 12 which extend across the cap top and .portions 13 and 14 which extend across the skirt 3 lying in substantially parallel relationship as shown in FIGS. 1 and 4. Accordingly a tear strip 15 is formed between the scores as a continuation of the ear-6 which tear strip extends a substantialdistance across the cap.

The completed cap blank 20, from which thecap of FIGS. 4 and 5 is made, is shown in full in the bottom plan view of FIG. l. Enlargedsectional fragments of it are shown in FIGS. 2 and 3 with FIG. 2 being turned upside down from the showing in FIG. 1. The blank 20. is seen to be notched at 21 and 22 at the juncture of the ear sides 8 and 9 with the blank periphery 5. Most important, however, is the fact that the ear 6 has .a strip of metal lpunched out of it to form an elongated opening 23, which is shown `here as a slot having parallel sides 24 and 2&5 and inner and outer curved ends 26 and 27 respectively. Looking at the flat blank of FIG. l, the elongated slot 23 is seen to have its longitudinal center line coincide with the longitudinal axis of theear 6. The inner end 26 of the slot extends radially inwardly -to a position slightly beyond the innermost extent of the notches 21 and22. Looking at it another way, the slot 23 extends inwardly so as to lie between the score lines 13 and 14 just inwardly of the position where those score lines meet the notches 21 and 22. The position of the outer end 27 of the slot 23 is not as signicant as that of the inner end 26 and is shown as being in the portion of the ear 6 which is suitably embossed at 6a to facilitate gripping. Though for the purposes of illustration the elongated opening 23 has been shown and described as a slot having parallel sides it is to be understood that the invention is not limited thereto. Elongated openings of different shape, so long as they are capable of serving the intended purpose, are encompassed within the invention.

Having on hand a scored, notchedand punched blank 20 the next step in the forming of the cap of the invention is the cupping or drawing operation wherein the peripheral skirt portion 3 of the flat blank 20 is drawn laterally with respect to the central or top portion 2. The result of this is depicted in FIGS. 4, 5 and 8. In the forming or cupping of a cap out of the flat yblank 20, the metal of the skirt portion 3 is rather severely worked or crowded by the varied reduction of its diameter from the turning line 4 out to the blank periphery 5 as the skirt portion is moved into lateral position. What has not heretofore been appreciated is that the metal in the part of the skirt from which th ear extends is placed under considerably greater stress than the remainder of the skirt. Considering then the fact that in its scored areas the skirt has been thinned out and weakened before the cupping step is carried out, i-t can be appreciated that if no effective safeguard is introduced the effects of the working are most seriously manifest in the score areas.

In prior art caps such `effects as the deformation, distortion,closing up or side overlapping of the scoring or various combinations of those effects, increased in severity as the movement of the metal increased toward its maximum at the free edge of the skirt. These effects prevailed at b-oth sides of the tearing ear though not necessarily to equal extent. This condition gave rise to unpredictable, non-uniform tearing characteristics. Commonly these run toward too great resistance to tearing but then the contrary also takes place.

Turning now to FIGS. 4 and t8, one can see how the provision and position of the elongated opening or slot 23provide the solution to the prior art problems. This is rather graphically illustrated by the shape which the slot 23 has taken in FIGS 4 and 8 as distinguished from its initial form in the blank of FIG. 1. Basically it is seen that the side walls 31 and 32 of the slot have yielded to the stress created in the whole of the skirt and particularly in the portion thereof from which the ear extends in the foi-ming of the skirt out of the that. As illustrative of where the stresses act it is seen that the top part of the slot at 30, as viewed in FIG.v 4, is closed in into somewhat of a point instead of being rounded as seen at 26 in FIG. 1. Continuing on'down from that the slot is narrowed with its sides 31iand 32 being movedy in toward each other down through the neck portion 7 of Ithe ear to about the position 7a where the ear bends laterally. Going kback to`FIG. 4 it is seen that the top 30 ofthe slot lies substantially above a horizontal line passed through the lower end portions of the scorelines. This then assure thatpat vtheioutset, there is any open slot lying in opposition to the position where ,the slits 21 and 22 are closedup'and also in opposition to the position where the scores 28 and y29 commence. The fact that this slot has been narrowed shows graphically that the stress in the skirt in the'i'zone of these positions is taken up in collapsing the sides of the slot toward each other.

Thought the portions 'of the skirt which have been thinned vdown in the scoring are less capable of resisting the distortive forces' created by the stress in the skirt than is `the lunscored portion, the scored portions are, never- 4theless, able to resist those forces t'o agreater extent than are the side walls of the slot. Thus before the scores are altered in formation vto such an extent as to make any material difference in the tearing characteristics, the forces are transmitted to and act upon the walls ofthe slot clos-v ing the same up to a certain extent. Y l n The fact that the slot 23 extends down the tearing ear to the position 35 which, asseen from FIG. 5, is a con` siderable distance beyondthe bend line 7d provides a further leasing of the stresses on the lower end of the scores. This is because the increased length of the slot beyond lthe stress position enables the sides of the slot to be bent in more easily through the stress position: Fortunately the extension of the slot downward provides no detrimental effect in the ear and may in fact enhance the grippingof` the lear but to do tha-t to any substantial extent it is preferable to continue .the slot further down as is illustrated in FIGS. 10 and 1l. The elimination of restriction against collapsing the sides of the slot gives more room for the metal of the tearing ear, at least the portion 7 thereof, to ilowy away from the ends of the scores and accordingly providesa greater safeguard against a closing or other interference with those scores.`

Though the metal in all of the vskirt is rather severely stressed in the fori-ning of the skirt'3 from the at blank into the cylinder, it appears, from graphical studies that have been made inconnection with the invention, that thestress is not as severe in the remainder of the skirt 3 as it is inthe narrow portion thereof from which the tearing carg extends. rThe extension of the ear from a `portion of the skirt appears to prevent flow `of the metal in that portion ofthe skirt which would, to a certain `extent,lyrelieve the stresses. Apparently, also, in the absence of an elongated opening -or slot such as 23, the stress in the portion of the skirt between the scores 13 and 14 and from which the ear 6 extends has a re'- active effect` which has been causing the disturbance or blocking of the scores in the positions 28 and 29, as

seen in FIG; 4, where the scores extend into the closed up ends of the notches 21 and 22. N

It is then this different flow path of the metal in the por! tion within the score lines, as against that outside of the score lines, which seems to have been causing the trouble in the prior art. This condition, however, as just pointed out and as shown by the shape that the slot 23 adopts when the blank is cupped, is taken care of by, or one might say4 that the action of it is absorbed, in closing in the sides of the slot rather than disturbing the score. This does not interfere with the strength of the ear 6 as needed for pulling on it to break the scores and tear out the tear strip 15 so, as against all the prior art efforts to solve the problem, the solution here is a real solution and one which is unaccompanied by any drawbacks.

Turning now to consideration of the condition of the cap afterl it is secured in place on the bottle finish by spinning or other securing action, attention is directed to FIGS. 6, 7 and 9. The cap 1, as indicated in FIG. 4, has of course been provided with a suitable lining or gasket as indicated at 40, which, as seen in FIG. 7, is sealingly engaged with the bottle bead or finish 51, being deformed and spread `over that finish in the course of the securing action. To eect the securing of the cap calls for further reduction of the diameter of the previously formed skirt. Also this reduction will normally be in stepped annular zones since the skirt of the cap will be drawn in under-y dustry, the cap of the invention can be satisfactorily secured to a variety of other finishes.

Proceeding with a consideration of the cap as applied to the illustrative finish just referred to, it Will be seen that in the securing of the cap in place on the bead one portion 45 of the skirt thereof is drawn in on an incline underneath and against the surface 52 of the bead, while the remaining portion 46 of the skirt is drawn in to the greatest extent being formed against the bottle neck 50.

The inward forming of the portions 45 and 46 of the skirt 3 which, of course, includes the neck portion 7 of the tearing ear, a strip 47 of which is inclined inwardly the same as the portion 45, is preferably achieved by the use of spinning rollers which move the metal inward progressively. This, of course, further reduces the radius of the inwardly formed skirt portions additionally.

stressing the metal thereof beyond the stresses imposed in the forming of the cap skirt 3. This action can be quite severe and, as pointed out in the foregoing, the results may be very considerable, depending upon such things as the setting of the forming rollers and the quite commonly encountered variations in the glass finish and neck. It can be readily appreciated then that, in the prior art, it may have been possible to construct a cap which would be satisfactory down to this securing action. It has been more dicult to control what happens in the actual securing and thus what the final condition will be with regard to the destruction and removal of the cap by grasping the tearing ear and tearing along the score lines.

Looking now at FIGS. 6 and 9 it will be seen, however,

that the elongated opening, or slot, in the ear introduced locking surface 52 of the bottle finish. This upper end The upper end 48 theie- 7. 43 which is done to almost a point, lies far enough below the lowermost end of the gasket 40, as seen in FIG. 7,

that no weakening of `the pressure retention can result.

Then a portion .41 of the slot extending down from the end 48 is seen to be narrowed down to a slit which continues down to a position 49 below the free end edge 5 of the skirt. Then the slot, or opening, opens out with diverging sides 42 and 43 to the remote end 44 which still retains substantially its original width.

Again the manner in which the slot and the ear is further reduced in width -by the securing of the cap on the bottle finish gives graphic illustration of the manner in which the stress in the skirt, created by the securing, is absorbed in the slot, thereby protecting the scores and particularly the lower ends 28 and 29 thereof, against dis.

tortion or closing up to sufficient extent to materially interfere with the tearing action. Here, also, the shape of the slot illustrates the manner in which the forces act down through the commencing portion, or neck, 7 of the tearing ear. As seen, these forces act to close in the slot to a position a little below the bead and then still close in the sides of the slot on the inclines as seen bythe sides 42 and 43.

It will also be seen thatthe notches 21 and 22 have been closed slightly further than in the runapplied form of the cap as seen in FIG. 4. Nevertheless these are not quite closed up nor is the portion 41 of the slot so that safeguards still remain against the bead and bottle neck being so undersized that complete closing could take place, with the stress then being centered in the score ends 28 and 29. i

It is believed to be apparent, from the showings in FIGS. 6 and 7, that all one needs todo to remove the cap 1 from a bottle is to grasp the gripping portion 6a of the ear 6 and, in moving it away from the bottle neck, start to tear along the scores at 28 and 29 and then continue vthat ltearing more easily as the scores open up in their upward extent. One important aspect of this form of removal is that once the tear strip is free, pairt way across the gasket 40, relief of the pressure within the container will commence. This acts as a safeguard against results such as are achieved in some of the prior art hand' removable closures, where the pressure is not relieved until the cap is destroyed to sutiicient extent to cause it to blow off With consequent chance of injury to the consumer.

In FIGS. l and 1l a modified form of slot is shown and indicated generally at 60. In FIG. 10 the slot 60 is shown as having an inner end 61 and a pair of elongated sides 62 and 63 which structure coincides with the slot 23 in FIGS. 1 to 9. The outer end of the slot 60, however, differs from the previous showing by opening up into a bulbous portion 64, forming the center portion of the gripping embossing 6a. When a cap formed from the blank of FIG. 10 is sealed onto a bottle, it can be seen that the inner end portion of the slot 60 substantially closes up into a slit 65 from which the sides 66 and 67 diverge to the enlarged bulbous end portion 64. In this form of the invention the bulbous portion 64 serves to enhance the grip that may be achieved on the tearing ear by the consumer. i

'In FIGS. l2, 13 and 14 the application of the invention to a cap provided with scores on its exterior surface b, b rather than onits interior a, a is illustrated. To a large extent the blank 70 is the same as the blank 20 of FIG. l, the only difference being that the skirt 73 isformed downwardly from the circular top portion 72 about the bend line 74 so as to leave the score lines 75 and 76 extending into the metal from the outside instead of from the inside of the cupped blank. The scorre lines may extend in various directions, such as, but Without limitation to, sweeping inwardly toward each other on convex curves, or as straight lines diverging or converging as they extend across the blank from the tearing ear, but for simplicity of illustration the score lines 75 and 76,'as here shown, extend in parallel relationship across the blank.

This form of scoring has been-found to bc quite satisfactory for removal of a cap formed in accordance with the invention.

By reference to the formed cap of FIG. 14 the scores 75 and 76 are seen to have short portions 13a and 14a which extend down the skirt defining the skirt portion of the tear strip 15a. The portions 13a and 14a terminate at positions 28a and 29a closely adjacent the position where the notches 21a and 22a form closed slits.

In prior art caps, formed with external scores but lacking the elongated opening or .slot of the invention, the difficulties encountered in the closing-up of the scores at the positions 28d and 29a are little if any different from what is encountered when the scores are internal. Thus the need for a solution to that problem is also substantially as great. Again the solution is provided by the inclusion of an elongated opening 23a in thetear strip 15a and ear portion 6, the same as described with respect to FIGS. l through 1l. Again the solution is graphically shown by the closing vup of the upper end 30a of the opening 23a and the closing in of the sides 31a and 32a thereof. The re'maining of the tearing ear 6, the neck portion 7 thereof,` the bend line 7a and the gripping element 6a, at the end .of the tearing ear, needy be no different from those of the previous forms, so are illustrated as having the same structure and carry the same reference characters.

Caps formed in accordance with the invention, with a strain absorptive elongated opening in the ear, have been found to perform as designed when secured to various bottle finishes. In the first place the retention of high pressure is not interfered with since the upper end of the elongated slot, in each instance, lies below the gasket and is, in any event, substantially closed up in the securing of the cap to the bottle. The scores, however, are left sufficiently undisturbed to enable one with a normal, or even less than normal, grip to start the teatr and complete the tearing within the range of the` few pounds pull which bottle users are readily able to exert.

More importantly, however, the .various factors above described, which have heretofore introduced variations in the securing which could not be guarded against, have been taken care of by the inclusion of the elongated slot position as it is in the tear strip and tearing ear of the cap of the invention. This introduces a break through in to the hand removable caps for bottles, jars and other containers, so that this convenience, heretofore denied the public by factors Whichcannot be controlled, now becomes readily available.

Since certain changes in carrying out the above method and certain modifications in the article which embody the invention may be made without departing from its scope, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A lightweight metal closure cap adapted to bel secured over a lip bordering the opening of a container neck, said cap comprising a disc-like top portion, a laterally depending skirt therearound having a smooth cylindrical surface terminating in a substantially circular lowermost free edge, a pair of weakened tearing lines extending across said cap skirt and into said top portion, saidlines defining a tear strip therebetween forming an integral part of said cap skirt and top portion, said tear strip extending downwardly away from said free edge in a short extension of said skirt and then extending radiallyoutwardly away from said skirt in a gripping portion to facilitate tearing, a radially elongated slot formed in said tear strip, said slot disposed within said short extension of said tear strip whereby severe distortion of said Vweakened lines is protected against through deformation of said slot which deformation reduces the resistance offered by said short skirt extension of said tear strip to circumferential movement of metal in said skirt during initial forming and subsequent applying of said cap.

9 10 2. A lightweight metal closure cap as in claim 1, where- 2,186,519 1/ 1940 Buono 21S-45 in said slot extends within said tear strip from the area 3,130,056 4/ 1964 Taylor et al. 215-46 of said skirt free edge to a point in said radially outwardly FOREIGN PATENTS extendmg gnppmg pomon' 5 486,544 6/1938 Great Britain.

References Cited by the Examiner LOUIS G. MANCENE, Primafy Examiner.

UNITED STATES PATENTS FRANKLIN T. GARRETT, THERON E. CONDON,

Examiners. 1,239,238 9/ 1917 White 215-46 I. B. MARBERT, Assistant Examiner. 

1. A LIGHTWEIGHT METAL CLOSURE CAP ADAPTED TO BE SECURED OVER A LIP BORDERING THE OPENING OF A CONTAINER NECK, SAID CAP COMPRISING A DISC-LIKE TOP PORTION, A LATERALLY DEPENDING SKIRT THEREAROUND HAVING A SMOOTH CYLINDRICAL SURFACE TERMINATING IN A SUBSTANTIALLY CIRCULAR LOWERMOST FREE EDGE, A PAIR OF WEAKENED TEARING LINES EXTENDING ACROSS SAID CAP SKIRT AND INTO SAID TOP PORTION, SAID LINES DEFINING A TEAR STRIP THEREBETWEEN FORMING AN INTEGRAL PART OF SAID CAP SKIRT AND TOP PORTION, SAID TEAR STRIP EXTENDING DOWNWARDLY AWAY FROM SAID FREE EDGE IN A SHORT EXTENSION OF SAID SKIRT AND THEN EXTENDING RADIALLY OUTWARDLY AWAY FROM SAID SKIRT IN A GRIPPING PORTION TO FACILITATE TEARING, A RADIALLY ELONGATED SLOT FORMED IN SAID TEAR STRIP, SAID SLOT DISPOSED WITHIN SAID SHORT EXTENSION OF SAID TEAR STRIP WHEREBY SEVERE DISTORTION OF SAID WEAKENED LINES IS PROTECTED AGAINST THROUGH DEFORMATION OF SAID SLOT WHICH DEFORMATION REDUCES THE RESISTANCE OFFERED BY SAID SHORT SKIRT EXTENSION OF SAID TEAR STRIP TO CIRCUMFERENTIAL MOVEMENT OF METAL IN SAID SKIRT DURING INITIAL FORMING AND SUBSEQUENT APPLYING OF SAID CAP. 